UPPER WEST SIDE — For sale by owner: one curbside parking spot, slightly used.

That's the idea behind a new mobile device application called Parking Auction, which lets drivers auction off their parking spot — even a free, curbside spot — to the highest bidder.

"People say, 'Oh that's ridiculous, I'll never pay for free parking.' But they don't understand how much they're already paying in time and gas wasted," said Parking Auction's Brian Rosetti, who co-founded the business with fellow Upper West Sider Nick Oliva.

Oliva came up with the idea when he was sitting in his car one day waiting for a parking spot to open up, and began to think about how much time and money he was wasting.

"Over the course of a year, the cost of waiting for free parking is a lot," Rosetti said.

Drivers on the hunt for elusive on-street parking spots not only waste their own time and money, they create broader urban ills, Rosetti said. The aimless driving adds to air pollution and traffic congestion, which Mayor Michael Bloomberg says costs the city's economy $13 billion a year.

On the Upper West Side, drivers are paying a high price for curbside parking, according to a 2008 study by the nonprofit advocacy group Transportation Alternatives. The report surveyed a 15-block stretch of Columbus Avenue and found that drivers spend 50,000 hours a year looking for parking, which costs them $130,000 a year in fuel.

Those drivers traveled 366,000 miles a year in search of a parking spot, which generates 325 tons of carbon dioxide annually, the study found.

Parking Auction could help cut down on those parking-related problems because the app lets drivers quickly identify available parking spots, Rosetti said. They've partnered with Clean Air NY, an environmental group that's touting Parking Auction as a tool for cutting pollution.

The app is simple to use. Drivers — or sellers — readying to leave their parking spot post their general location and time when they'll be leaving their spot on Parking Auction and name a price, say $5.

Meanwhile, the buyers — drivers in search of parking — check Parking Auction and see the spots pop up on a map. They bid, and if a seller accepts, that spot user then sends the buyer an exact location and the make and model of their car.

Some question whether it's legal to "sell" a parking spot, but Rosetti said the start-up's lawyers have assured them they're on the right side of the law. The transaction is considered legal because Parking Auction sells information about when a spot will be available, not the space itself, he said. "It’s like a logistics company selling information about which road to take," Rosetti said. "It’s providing convenience."

However, a Department of Transporation spokesman said "it appears" Parking Auction is a "parking reservation system," which wouldn't be allowed under city traffic rules.

To influence the seller, the buyer can include information such as whether they have kids or seniors in the car and whether they need to park immediately.

Sellers are supposed to alert buyers if their car isn't likely to fit into their spot. For example, if an Escalade wanted to buy a spot that a Mini Cooper is leaving, it would be up to the Mini driver to tell the Escalade to look elsewhere. Sellers lose the sale if they try to sell to a buyer who doesn't fit.

Parking Auction's buyers and sellers are rated the way Amazon users are, so there's an extra incentive to be honest, Rosetti said.

But there's a catch: If another driver pulls up who wants the spot but didn't find out about it on Parking Auction, the seller has to give up the spot to that person.

Rosetti and Oliva hope to eventually partner with parking garages that could list spaces for sale. Right now the Parking Auction map lists nearby garages.

Parking Auction went live earlier this year, and Rosetti and Oliva are focusing on building a critical mass of users on the Upper West Side. When they reach that goal, they hope to expand and attract more investors. Right now Parking Auction is funded by a few private individuals.

"This is a novel approach to a serious problem," Rosetti said. "We want Upper West Siders to be the pioneers to help adopt this technology."

Want to try Parking Auction? Users who register using the promotional code "BRIAN" will get 25 Parking Auction Credits.

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